Light sensitive iminoquinone diazide and material for the photomechanical preparation of printing plates therewith



United States Patent ,592 18 Claims. (Cl. 96-33) In presensitizedmaterial useful for the photomechanical preparation of printing plates,the o-quinone diazides and p-quinone diazides, including in particularthose substituted in the nucleus by sulfonic acid ester or sulfonamidegroups, have attained industrial importance, and also the iminoquinonediazides. As a result of the pronounced light-sensitivity thereof,irninoquinone diazides of the benzene series, derived from a1,4-phenylene diamine substituted in an amino group by an aryl sulfonylradical, which togther with other irninoquinone diazides are describedin German Patent 901,500, haveproved very satisfactory. When exposed tolight, the iminoquinone diazides are converted to products of highmolecular weight which are more diflicultly soluble in dilute alkalis,dilute acids, or organic solvents than are the iminoquinone diazidesthemseves. This property provides the basis for the suitability of thesecompounds for the production of images and the preparation of printingplates since, after reproduction coatings prepared therewith have beenexposed under a master to light, the remaining light-sensitive portioncan be selectively separated from the light decomposition product, usingthe developers described above. From a negative original,

positive images or printing plates are obtained, and vice versa.

In further work on iminoquinone diazides as light sensitive compounds, areproduction material containing iminoquinone diazides in the coatinghas been found which is particularly suitable for the preparation ofimages or printing plates. In this material, the iminoquinone diazideswhich constitute the reproduction coating, or which are containedtherein, correspond to the general formula Inthis formula R is an arylor substituted aryl radical, and R is a member selected from the groupconsisting of the residue NH in which R" is a heterocyclic radical, andheterocyclic residues.

3,180,732 Patented Apr. 27, 1965 USOr-N Formula 1 P" i H 0011; l ISOiNC\ Formula 2 t I CH CH za z-*N\ CH Hg Formula 3 SOa-N\ 0 GHQ-CFormula 4 S\Oz N H OHfl-OH: sol-N Nso1oHi I l. a

Formula 5 The iminoquinone diazides of the invention are, for

practical purposes, insoluble in water but are soluble in organicsolvents. They are applied in known manner, in solution in organicsolvents, to suitable supports, e.g. metal plates or metal foils,preferably aluminum or zinc, or paper. It can be advantageous if resins,preferably alkali-soluble resins, are applied in association with thelight sensitive compounds to the surface of the supports. They favorfilm-formation and increase the adherence of the image, i.e. theprinting image remaining on the support after the development of theexposed reproduction coating, because the light reaction products of theiminoquinone diazides react with the resins which are capable of beinganchored to the supports. For example, the phenol formaldehyde resinnovolaks commercially available under the registered trademark Alnovoland the conversion products obtained therefrom by etherification withchloroacetic acid have proved to be very suitable resins for thispurpose. Processes of preparation for these etherification products aredescribed in detail in German patent specification No. 1,053,930, inExample 5.

For special effects, e.g. to prevent crystallization in the reproductioncoating and/ or to increase resistance to the developer, it may beadvantageous for mixtures of the iminoquinone diazide compounds of theivention to be used in the light sensitive coating.

For the preparation of a printing plate from the presensitized materialof the invention, the reproduction material is exposed to light under amaster. The image formed is at first barely visible. It becomes cleareronly after development, when it becomes a pale yellow color. Ifdyestuffs are added to the coatings, the images have the color of thedyestuifs; this has the advantage that the development process can bebetter followed. Dyestufr additions do not interfere in any way with thepro ess, because it is only with the light decomposition products thatthe dyestuffs form precipitation products during development which areinsoluble, and not with the light sensitive substance. Here, too, dilutealkalis are suitable as developers, e.g., solutions of alkali metalsalts of phosphoric acid and the alkali metal salts of the various formsof silicic acid. Organic bases, e.g. the ethanol amines, in the form ofaqueous solutions thereof, may also be used as developers. In somecases, good results may also be obtained by using acid developers, e.g.dilute aqueous solutions of phosphoric acid, to which small amounts ofwater-soluble, organic solvents may be added, e.g. ethylene glycolmonomethyl ether.

In the case of development with; solutions containing alkali silicate,water-conduction in the image-free parts of the surface of the supportis adequate after the alkaline treatment, so that further treatment withdilute acids, such as is usually performed in the printing trade, is notnecessary.

The light decomposition products of the iminoquinone diazides of theinvention are characterized by excellent oleophilic properties and theyaccept greasy ink with great facility. This is of great technicalimportance because the printing plates once ready for printing will give4-nitro-benzene-2-sulfarylamides are formed. These intermediate productsare condensed in solvents with aryl sulfonamides, in the presence ofcopper powder and alkali carbonate. The chlorine in the one-position isthus replaced by the aryl sulfonamide residue. The nitro compoundsobtained can be reduced by known processes,

eg. by means of sodium dithionite, and theamines thus.

obtained are diazotized in water-miscible solvents, e.g.

4: in a mixture of dimethyl formamide and glacial acetic acid. Theiminoquinone diazides, for the. most part, precipitate out in the formof sparingly soluble compounds, or they can be precipitated by theaddition of Water.

(2) 4-nitro-1-amino-benzene-2-sulfonic acid is reacted with aromaticsulfochlorides and the 1-aryl-sulfamino-4- nitro-2-benzene-sulfonicacids thus obtained are converted into sulfo chlorides which are thenreacted with aromatic bases. The nitro compounds thus obtained arefurther processed as described above under (1).

The list below gives:

rtzI's 4 5 0. Percent 1 PhenyL. Pyridyl-(2)-arnin0 -164 O. 120 B 2 doG-methory-benzthiazolyl- -2l7 0. 5 A

(2)-amino.

3 do- Pyrrolidino -164 0. 5 B

4 .do Morph0liuo 0.5 B

5 dolVIQnomethanesuItOnyl- 17a 0. 25 B piperazino.

The invention will be further illustrated by reference to the followingspecific example:

Example One part by weight of the diazo compound l-benzenesulfonylimino-Z-(pyrrolidino sulfonyD-benzoquinone- (1,4)-diazide-(4)corresponding to Formula 4 and 0.3 part by weight of a condensation.product of phenol formaldehyde novolak and chloroacetic acid, cg. acondensation product obtained from. the phenol formaldehyderesinfAlnovoli and chloroacetic acid by the process described in Example5 of German patent specification No. 1,053,930, are dissolved in amixture made up of parts by volume of methyl glycol and 20 parts byvolume of dimethylformamide. A mechanically roughened alumi num foil iscoated with this solution on a plate whirler and subsequently dried atC. After exposure under a transparent negative master, development witha 0.5 percent aqueous solution of 'trisodium phosphate, wiping over with1 percent phosphoric acid, and inking with greasy ink, 21 positiveprinting plate is obtained which is capable of long runs.

For the preparation of the diazo compound correspondingto Formula 4,4-nitro-l-amino-benzene-2-sulfonic acid is condensed with benzenesulfochloride in pyridine, the condensation product obtained is isolatedin the form of the sodium salt, and the latter is reacted withphosphorus pentachloride to form the4-nitro-l-benzenesulfonylaminobenzene2-sulfonic acid chloride; Thiscompound is re acted in known manner with piperidine. The nitro compound(melting .point -146 C.) is dissolved in a dilute solution of sodiumhydroxide and the boiling solution is reduced by addition of sodiumdithionite. The resulting amine is precipitated from the mixture byaddition of acetic acid, filtered by suction, and recrystallized frommethanol, the crystals melting at 174-175 C.

The amine is dissolved in a mixture of equal parts of dimethyl formamideand acetic acid and, at a temperature below +5 C.,' is diazotizzed byaddition of a 40 percent solution of sodium nitrite in water. Theresulting diazo compound is precipitated by addition of water,

l IF

in which R is an aryl group, R is a member selected from the groupconsisting of the residue NH--R", in which R" is a heterocyclic group,and heterocyclic residues wherein a nitrogen atom of the heterocyclicresidue is directly attached to the S group.

2. A compound having the formula 3. A compound having the formula OCH;

II CH1-CH5 Soy-N OHFOHZ 5. A compound having the formula 6. A compoundhaving the formula CHPCHQ 7. A presensitized printing plate comprising abase material having a coating thereon, the coating comprising acompound having the formula SO R' iii in which R is an aryl group, and Ris a member selected from the group consisting of the residue --NHR", inwhich R" is a heterocyclic group, and heterocyclic residues wherein anitrogen atom of the heterocyclic residue is directly attached to the S0group.

8. A presensitized printing plate comprising a base material having acoating thereon, the coating comprising a compound having the formulaSOr-N 9. A presensitized printing plate comprising a base materialhaving a coating thereon, the coating comprising a compound having theformula 10 OCHQ 10. A presensitized printing plate comprising a basematerial having a coating thereon, the coating comprising 2 11. Apresensitized printing plate comprising a base material having a coatingthereon, the coating comprising a compound having the formula 12. Apresensitized printing plate comprising a base material having a coatingthereon, the coating comprising a compound having the formula I I] GE-CH SO -N N SO --GH; I I OHr-C-Hg ILBID 13. A process for making aprinting plate which comprises exposing a coated base material to lightunder a 7 8 master, the coating comprising a compound having the formulain which R is an aryl group, and R is a member selected from the groupconsisting of the residue -NH-R, in which R" is a heterocyclic group,and heterocyclic residues wherein a nitrogen atom of the heterocyclicresidue is directly attached to the S0 group, and treating the exposedcoating with a developing solution.

14. A process for making a printing plate which comprises exposing acoated base material to light under a master, the coating comprising acompound having the formula so, 7 if H sorr'q- U N and treating theexposed coating with a developing solution.

15. A process for making a printing plate which cornprises exposing acoated base material to light under a master, the coating comprising acompound having the formula OCH3 and treating the exposed coating with adeveloping solution.

16. A process for making a printing plate which comprises exposing acoated base material to light under a master, the coating comprising acompound having the formula a to and treating the exposed coating with adeveloping so- 18. A process for making a printing plate whichcomlution. prises exposing a coated base material to light under a 17. Aprocess for making a printing plate which commaster, the coatingcomprising a compound having the prises exposing a coated base materialto light under a formula 7 master, the coating comprising a compoundhaving the 5 formula [3 r 10 I 5 on on SO. 1 I- I 1; soi-N NS0aOH: I/CHIOE, l CH -Caz s0,-N\. /0 Y 15 CH1CHg N,

it and treating the exposed coating with a developing so- 20 lution.

No references cited.

and treating the exposed coating with a developing solution. NORMAN G.TORCHIN, Primary Examiner.

13. A PROCESS FOR MAKING A PRINTING PLATE WHICH COMPRISES EXPOSING ACOATED BASE MATERIAL TO LIGHT UNDER A MASTER, THE COATING COMPRISING ACOMPOUND HAVING THE FORMULA